A study by Swiss researchers concludes that transaction malleability attacks could not have accounted for Mt. Gox's missing millions

In an email, Wattenhoffer said the study has not been submitted to a peer-reviewed journal, adding "We will do this eventually, but reviewing takes time, and in this case we felt that some people might be eager to hear the news before the usual several-months peer-review cycle is over."

While observers on the Bitcointalk.org forum welcomed the study, they also cautioned that it only went back as far as January 2013.

"It's possible Gox was hit much harder in previous years," one commentator wrote. "Although that would also mean the amount of time they spent oblivious to the problem increases."

Software developer Mike Hearn, who works on bitcoin-related projects, welcomed the study's findings. "People were raising the alarm about this claim almost as soon as it was made by Mt Gox. Although in theory their explanation could have worked (if we assume really bad decisions on their part like not investigating failed withdrawals and just repeating them), the vast sums of money being talked about stretched credulity. And nobody else had reported observing lots of mutated transactions. Now we have data to prove this was correct," he said via email.